// ex6_1.cpp
#include <iostream>
#include <cctype>

int main(void)
{
    using std::cout;
    using std::cin;

    char ch;

    cin.get(ch);
    while (ch != '@')
    {
        if (isalpha(ch))
        {
            if (islower(ch))
            {
                //toupper(ch);
                ch = ch - 'a' + 'A';
                cout << ch << "\n"; 
            }
            else if (isupper(ch))
            {
                //tolower(ch);
                ch = ch - 'A' + 'a';
                cout << ch << "\n";
            } 
        }
        cin.get(ch);
    }
}

